The present invention relates to rotating disk data storage devices, and in particular, to use of such storage devices in a motor vehicle environment.
The latter half of the twentieth century has been witness to a phenomenon known as the information revolution. While the information revolution is a historical development broader in scope than any one event or machine, no single device has come to represent the information revolution more than the digital electronic computer. The development of computer systems has surely been a revolution. Each year, computer systems grow faster, store more data, and provide more applications to their users.
The extensive data storage needs of modern computer systems require large capacity mass data storage devices. While various data storage technologies are available, the rotating magnetic rigid or hard disk has become by far the most ubiquitous. Such a disk drive data storage device is an extremely complex piece of machinery, containing precision mechanical parts, ultra-smooth disk surfaces, high-density magnetically encoded data, and sophisticated electronics for encoding/decoding data, and controlling drive operation. Each disk drive is therefore a miniature world unto itself, containing multiple systems and subsystems, each one of which is needed for proper drive operation. Despite this complexity, rotating magnetic disk drives have a proven record of capacity, performance and cost which make them the storage device of choice for a large variety of applications.
Rotating magnetic disk drives were originally installed in so-called mainframe computing environments, which typically maintained a very controlled environment. That is, due to the complexity and sensitivity of the various computer system components, temperature, humidity and other factors were maintained within a narrow range. However, as computing machinery has become more ubiquitous, it has been necessary to design components which will tolerate a wider range of environments. Thus, disk drive storage devices have progressively been designed for use in desktop personal computers, and eventually in laptop and other portable devices.
Given the advantages of rotating magnetic disk drives, it would be desirable to use such devices in an even greater range of applications. One potential area of application is in on-board data storage permanently installed in an automobile.
As in well known, modern automobiles are incorporating ever greater electronic capabilities. A modern automobile typically contains an on-board processor, on-board memory in the form of semiconductor memory, and various I/O devices such as sensors, gauges, control mechanisms, warning systems, and the like. Thus, while it is not always recognized as such, a modern automobile contains all the components while define a basic computer system. It would be desirable to use this on-board computer system for an even greater range of tasks than is typical today. These tasks may be related to the function of the automobile itself, or may simply be tasks for the convenience of the driver or passengers, such as providing entertainment, news, or other information.
When the on-board computing system of a typical automobile is compared with that of a desktop computer, one glaring deficiency of the typical automotive computing system is data storage. A typical desktop system contains one or more rotating magnetic disk drive storage devices, capable of storing massive amounts of data. The automotive system typically does not, and is thus generally used for tasks which do not require this magnitude of data storage. The incorporation of disk drive storage in the on-board systems of automobiles would open up a new range of capabilities for such systems.
Existing rotating magnetic disk drive data storage devices were not designed for automotive use. Conversion of such drives to automotive use requires consideration of numerous design implications, and the adaption of new strategies for the design and use of such drives. There is therefore a need for design and operational modifications which will enhance the ability of such drives to operate in a motor vehicle environment. In particular, existing rotating magnetic disk drive storage devices do not operate well at temperature extremes, and may require considerable time to power up and provide data.
In accordance with the present invention, certain data stored on a rotating magnetic disk drive data storage device installed in a motor vehicle is presented serially to the user. This data is buffered and the presentation context is saved in sufficient amount to transcend a time interval of data unavailability when a disk drive is initially powered up.
In the preferred embodiment, the disk drive is used, among other things, for storing and retrieving multimedia data which is presented serially to a user. An example of such multimedia data is digitized music, although other examples exist. When the vehicle is shut off and the drive is powered down, the data to be presented in the immediate future is saved in a non-volatile but immediately available buffer, which is preferably a dynamic semiconductor random access memory (RAM) which receives power at all times from the motor vehicle""s battery. The xe2x80x9ccontextxe2x80x9d of presentation, i.e., the multimedia selection or selections being played, their order, and the point of interruption is also saved. The amount of data saved in the buffer is sufficient to span the time interval that it takes the disk drive to power up and become data accessible. In an automobile which may be subject to extreme cold when parked, this could be several minutes.
In one embodiment, an estimate is made of the amount of time required to power up the disk drive, and a variable amount of data is buffered sufficient to span the estimated interval.
Preferably, the buffer is a general purpose buffer for use by the vehicle""s on-board computer system. When the vehicle is running, this buffer may be used for storage of vehicle operating parameters, control programs, user information, and other data. When the vehicle is not operating, the amount of buffer required for these other functions is considerably reduced, and thus the same buffer space can be used for storing multimedia data for playback during the time interval when the disk drive is unavailable, as described herein.
Thus, a data buffering system in conjunction with a disk drive as described herein enables data from the drive to be available notwithstanding the inherent lag time in powering up a drive. Such a buffering system is particularly beneficial when powering up a disk drive in adverse weather conditions.
The details of the present invention, both as to its structure and operation, can best be understood by reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which: